In a disaster zone, whether it’s the aftermath of a tornado or on a battleground, emergency medical personnel have to work fast to save lives. In an effort to speed good care, scientists have developed a handheld, battery-operated “flashlight” that can instantly sterilize wounds by beaming plasma at bacteria.

Plasma, gases that are produced in electrical discharges, is something of a rock star in intensive healing. Previous studies show that it effectively kills bacteria and viruses on skin and water surfaces and helps heal wounds. Why plasma is such a powerful cleanser remains largely unknown, but scientists speculate that reactions between plasma and the surrounding air can create “a cocktail of reactive species,” similar to those in our own immune system, that can kill pathogens. Another theory is that ultraviolet radiation plays a role, but the flashlight produces a very low amount of UV radiation, which makes it safer.

To test the device, the researchers from China and Australia created thick biofilms of Enterococcus faecalis, a bacteria that frequently infects root canals and is known to be highly antibiotic- and heat-resistant. After seven days of incubation, the biofilms had grown 17 cell layers thick. The researchers then exposed some of the biofilms to the plasma flashlight for five minutes, and found that it was able to kill the bacteria, even at the deepest layer. Control samples of biofilms continued to thrive.

When applied to wounds, the plasma from the flashlight would produce reactive and long-living particles that interact with damaged cells and kill them, explains study co-author Kostya Ostrikov, a professor at the University of Sydney, Australia. The plume of plasma produced by the flashlight is close to room temperature to prevent further damage to the skin during cleaning.

“In this study we chose an extreme example to demonstrate that the plasma flashlight can be very effective even at room temperature. For individual bacteria, the inactivation time could be just tens of seconds,” said Ostrikov in a statement.

The real innovation here is that the flashlight is battery-powered and portable. Plasma devices that are currently in clinical tests need external power sources like a generator or wall power or additional external handling systems. “We need a portable, simple, battery-operated device,” says Ostrikov. With the flashlight, the researchers hope blasting bacteria and sterilizing injuries will become an easier process in the field.

The device needs further clinical testing before it can be used commercially, but Ostrikov says it’s almost ready, and is inexpensive to produce. Each unit will cost around $100.

The results were published online in the Journal of Physics D: Applied Physics.